US2054364A - Eccentric grinder - Google Patents

Description

A. DE LE EUW ECCENTRIC GRINDER Sept 15, 1936.

5 Sheets-Sheet 1 Filed July 25, 1934 INVENTR W of 621 M ATTORNEY) w Sept. .15, 1936. A. L. DE LEEUW ECCENTRIC GRINDER Filed July 25, 1954 5 Sheets-Sheet 2 Ps INVENTOR Q 1 ATTORNEY Sept. 15,1936. A. L. DE LEEUW ECCENTRIC GRINDER Filed July 25, 1934 5 Sheets-Sheet 4 K INVENTQR W 615 94m ATTORNEY Sept. 15, 1936. A. L. DE LEEUW ECCENTRIC GRINDER Filed July 25, 1934 5 Sheets-Sheet 5 FIG. 9

Fl lurfllllllfl *INVENTOR 5C 94 M B 60mg f ar/ll ATTO NEY UNITED STATES PATENT OFFICE ECCENTRIC GRINDER Adolph L. De Leeuw, Plainfield, N. J assignor of one-half to Albert F. Nathan, New York, N. Y.

Application July 25, 1934, Serial No. 736,817

16 Claims.

This invention relates to the art of finishing metal surfaces and it is concerned more particularly with the finishing or grinding of a plurality of portions of a workpiece some of which may be arranged eccentric to the axis thereof.

A primary object of this invention is to finish simultaneously, by a grinding or similar operation, a plurality of cylindrical surfaces arranged eccentric to the axis of a workpiece and also eccentric to each other.

A further object of the invention is torender available a machine capable of simultaneously grinding a plurality of cylindrical portions of a workpiece arranged, respectively, concentric with and eccentric to the axis of the workpiece.

Another object of the invention is to provide an improved grinding machine adapted, at a single operation, and with a single setting, to grind a plurality of cylindrical portions of a workpiece 'arranged concentric with the axis of the workpiece and simultaneously therewith to grind a plurality of other cylindrical portions thereof which are arranged eccentric to the axis of the workpiece and also eccentric to each other.

An automobile crank-shaft is a typical example of a workpiece having cylindrical portions concentric with the axis thereof and other portions eccentric thereto and also eccentric to each 7 other, the cylindrical journals, which are adapted to befitted to the crank-shaft bearings of the motor block, being the concentric portions and the crank-pins being the eccentric portions. Therefore, in this application, one embodiment of this invention will be shown and described in connection with such a workpiece but it is to be understood that the invention is not limited to this specific embodiment.

Heretofore the grinding of crank shafts has been accomplished only by a plurality of successive grinding operations accompanied by a plurality of settings of the workpiece. The most approved method heretofore devised consisted in first setting up the crank-shaft in one position in a grinding machine and simultaneously grinding the concentric journals. When this operation had been completed the workpiece was shifted to another machine and, by a subsequent grinding operation, one (or a pair) of the crankpins was ground. This resetting of the workpiece and the successive grinding operations were repeated until all of the crank-pins had been ground. It is to be understood that in certain types of crank-shafts, the crank-pins are arranged in coaxial pairs and therefore two crankpins may be ground at the same time. This practice necessitated a plurality of settings of the workpiece in a plurality of machines and a plurality of succcessive grinding operations to finish a single crank-shaft.

By means of the present invention all of the journals and all of the crank-pins of a crank: shaft may be ground in one machine with a single setting of the workpiece and at a single grinding operation, regardless of the number of journals and crank-pins. l

The above mentioned objects have been attained by providing means, in the nature of a power driven chuck engaging one end of a crankshaft and a suitable support engaging the other end, torotate a crank-shaft on its longitudinal axis. This causes the crank-pins to revolve about the axis of the crank-shaft. To one side of the axis of the crank-shaft and with their axes parallel thereto are a plurality of rotatable circular grinding wheels, journaled on fixed centers, one adapted to operate on each of the concentric journals of the crank-shaft. Also, journaled at one side of the axis of the crank-shaft on revolving centers are a plurality of circular grinding wheels, one adapted to operate on each of said crank-pins. The center of each of the last named grinding wheels bears the same relation' to the axis about which it revolves as the crankpin, which it is adapted to grind, bears to the axis of the crank-shaft and each grinding wheel is arranged to revolve synchronously with the revolution of its associated crank-pin. During each rotation of the crank-shaft each crank-pin revolves bodily once about the axis of the crankshaft and'simultaneously therewith turns once about its own axis, thereby successively presenting the various portions of its periphery to the action of its grinding wheel. Likewise, because of its eccentric mounting, each eccentrically mounted grinding wheel revolves bodily once about its axis of revolution during each rotation of said crank-shaft. Therefore, synchronous revolution of the crank-pins and their associated grinding wheels will maintain the periphery'of each grinding wheel in contact with the cylindrical surface of the crank-pin it is adapted to grind.

Obviously, it is desirable that the grinding operation be performed in a minimum amount of time, and as the grinding is effected by relative movement between the periphery of the workpiece and the periphery of the grinding wheel, it follows that this relative movement should be at a rapid rate. This may be attained by rotating a relatively small grinding wheel at a relatively rapid rate while maintaining it in contact With the crank-pin. 7

It is well known that the percentage of waste when using small grinding wheels is materially I greater than the percentage of waste in large grinding wheels. Therefore, in order to mini- 'mize this waste and to preclude such vibration as might be set up by rapidly rotating parts I prefer to obtain the'desired peripheral speed by employing relativelylarge grinding wheels and causing them to revolve at a relatively slow rate.

This conveniently may be effected, as shown.

herein, by securing relatively large grinding wheels on a shaft adapted to be rotated synchro-; nously with the crank-Shaft. The wheels which grind the concentric journals are mounted coaxial with the shaft while the wheels adapted to grind the crank-pins are each mounted eccentric to the shaft, the angle and extent of such eccentricity corresponding to the angle a-nd'extent of eccentricity of the crank-pin which the wheel 'is adapted to grind. With' this construction each rotation of the shaft effects one rotation of each grinding wheel and also one revolution of each eccentrically mounted wheel which corresponds to the revolution of its associated crank-pin thereby maintaining the two. in peripheral con-- 7 tact.

Means is provided for effecting relative movement between the workpiece and the grinding Wheels to bring them together to initiate a grinding operation and to maintain them in contact during the operation.

' Inasmuch as the grinding wheels are relatively large and the crank-pins are relatively small the vide improved supports for each of the journals and for each of the revolving crank-pins, thereby to prevent the workpiece from being deflected .by the action of the grinding wheels thereon.

This has been attained by providing suitably formed steady-rests adapted to be shifted into supporting contact with the portions to be ground and giving to certain ones of. said rests orbital movements corresponding to the revolving motions of the crank-pins, thereby to maintain the rests in supporting contact with the crank-pins as thelatter revolve.

A still further object of the invention is to provide means for simultaneously dressing both the concentrically and eccentrically mounted grinding wheels. This has been accomplished by pro' viding a dressing tool. for each wheel; the dressing tools'for' the concentrically mounted wheels being adjustable in one direction into contact with the periphery of the wheel and in a transverse direction to cause the'tool to traverse across 701 responding to the revolution of the eccentrically the face'of the wheel. The dressing tools for the eccentrically mounted wheels also have these adjustments and in addition means is provided forgiving to these tools an orbital movement cormounted wheels, thereby to maintain the wheel and the dressing tool in relatively fixed position except for the rotation of the wheel and the above described adjustments of the dressing tool.

Although this invention hereinbefore has been described in connection with the grinding of cylindrical portions of a workpiece by synchronously revolving the workpiece and the grinding wheel, it is to be understood that the invention is not limited thereto. This invention also contemplates the grindingof workpieces, or portions of workpieces, which are not cylindrical in cross section and which have peripheral surfaces which are eccentric to the axis of, the workpiece.

This is accomplished by varying the ratio of" rotation of the workpiece to the revolution of the grinding wheel. For example, the workpiece may be given one rotation to two, three or more revolutions of the eccentrically mounted grinding wheel, in which case the cross sectional form of the workpiece may be substantially elliptical, triangular or of other desired shape as hereinafter will be more fully described.

Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom. in connection with the annexed drawings. 3

To enable others skilled in the art so fully to Fig. 4 is an enlarged sectional view, substan- V tially on the line 44' of Fig. 1, showing particularly an improved steady-rest for the work, later to be described. 7

Fig. 5 is an enlarged sectional view substantially on the line 5-5 of Fig. 1 showing particularly an improved wheel dressing device later to be described. a

Fig. 6 is a section on the line 6-6 of Fig. 4.

Fig. 7 is a side elevation of a portion of one of the grinding wheels showing its eccentric mounting on its drive shaft.

Fig. 8 is a section on the line 8-8' of Fig. 7.

Fig. 9 is a diagrammatic illustration, in plan, of a portion of a modified construction in which the grinding wheel is given three revolutions about the axis of its drive shaft to one rotation of the workpiece.

Fig. 10 is a diagrammatic illustration, in side elevation, of the grinding wheel and workpiece shown in Fig. 9.

Fig. 11 is a diagrammatic illustration showing the form of a workpiece which may be ground by revolving the eccentrically mounted grinding wheel twice for each rotation of the workpiece.

Referring more specifically to the drawings the invention is disclosed as embodied in a grinding machine comprising a base I upon which is secured side frames 2 and 3. These side frames support, intermediate their ends, bearings 4 and 5 within which isrotatably journaled a grinder wheel'drive shaft 6.

Slidingly mounted on guides I and 3 formed on one end of the side frames 2 and '3 is a carriage 1 which carries at one end a head-stock 8 and at the other end a tail-stock 9. Intermediate the head and tail stocks the carriage carries an adjustable work-support designated generally as S, later to be described. At their opposite ends the side frames 2 and 3 are provided with guides 2 and 3 respectively, upon which is translatably mounted a table provided with transverse guideways l0 to which is slidingly fitted a table I I forming a support for improved wheel dressing devices, designated generally as D, and which will later be described in detail.

Power to operate the machine may be supplied by a suitable motor M connected by a multiple belt drive B with a driving pulley l2 secured upon a reduced outer end of the shaft 6. Secured to the shaft 6, outside of the bearing 4 is a bevel gear l3 which meshes with and drives bevel pinions [4 and I5 secured, respectively, on shafts l6 and I1 journaled in bearings I6 I6 l6, l6 and 11 N respectively, secured to the side frame 2. The shaft I6 is utilized to rotate the work-holder and the shaft I1 actuates the wheel dressing devices as hereinafter will be explained.

Rotatably journaled in the head stock 8 is a spindle l8 to one end of which is secured a bevel gear I!) in mesh with a bevel drive pinion splined to the shaft [6 and adapted to be moved therealong by movement of the carriage I and the head stock carried thereby. To the opposite end of the spindle [8 there is secured a workholder or chuck 2| adapted to grip one end of a workpiece W which, as shown in Figs. 1, 2, and 3, may be a crank-shaft having a plurality of concentric journal portions J and a plurality of eccentric crank-pins P P P and P The opposite end of the workpiece may be supported upon a dead center 22 adjustably mounted in the tailstock 9.

i For the purpose of this disclosure there is shown herein a crank-shaft in which the crankpins are arranged 90 apart and the grinding wheels therefor are shown as mounted to operate continually thereon. It is to be understood, however, that any other form of crank-shaft may be ground, the grinding wheels to be mounted in accordance with the angular position of the crank-pins.

It is, of course, necessary that rotation of the work-holder be suspended for the purpose of removing a finished workpiece and replacing it with a new workpiece, but it is undersidable to stop the rotation of the grinding wheels for each of these changes. It is also necessary that, during the grinding operation, certain ones of the grinding wheels have a definite angular relation with respect to portions of the workpiece. Furthermore, it is desirable that all shocks and jars be eliminated when rotation of the workpiece is initiated.

To that end the shaft i8 is preferably formed of two aligned sections and a combined friction and toothed clutch, designated'generally as C, has been provided for coupling them together in driving relation. This clutch may be actuated, through suitable mechanism, from the right side of the machine by a control lever L. The clutch C is located within a housing secured to the sideframe 2 and affords means for stopping the rotation of the work-holder without interrupting the rotation of the grinding wheels. The friction clutch permits the Work-holder to be started gradually and the toothed clutch, which is of the single tooth variety, afiords means for insuring the proper phase angles of the crank-pins and their respective grin-ding wheels and for positively rotating the work synchronously with the rotations of the grinding wheels.

Fixedly secured upon the shaft 6 is a plurality of circular grinding wheels, one for each journal J and one for each crank-pin P to be ground. The grinding wheels for the journals are designated as G and the grinding wheels for the crank-pins P P P and P are designated, respectively, as G G G and G clearly in Figs. 7 and 8 the grinding wheels are preferably relatively large and are of ring-like form. These rings of abrasive material are clamped between circular disks 22 and 22 of which the former is provided with an annular shoulder 22 which affords a seat for the abrasive ring. A ring 22 of filling and cushioning material, such, for example, as lead, is preferably inserted between the abrasive ring and the shoulder 22. Suitable spacer rings R are preferably inserted between the disks of the grinder wheels to position the wheels accurately with respect to the portions of the workpiece they are adapted to finish. All of the grinder wheels, their supporting disks and the spacer rings are clamped together by means of draw bolts 23 passed therethrough and through flanges 24 and 25 secured to the shaft 6.

The grinder wheels G for the journals J are each mounted concentric with the shaft 6. The grinder wheels G G G and G are each mounted on the shaft 8 with its center eccentric to the axis of the shaft. The angle and extent of eccentricity of each of those grinding Wheels to the axis of the shaft 6 corresponds to the extent and angle of eccentricity of the crank-pin it is adapted to grind to the axis of the crank-shaft. This eccentric mounting and angular setting of the grinding wheels G G G and G may readily be effected by forming the disks 22 22 thereof with eccentric bores adapted to fit the shaft 5; forming key-ways g in said bores spaced 90 apart, and then placing all of those grinding wheel assemblies on the shaft 6 With their key-ways g in engagement with a single key K fitted into a suitable key-way in the shaft 6.

As shown in Figs. 1, 2, and 3 the ratio of the gears I 3| 4 and 2$--l9 is such that the shaft 6 and the spindle I 3, and, therefore, the grinding wheels and the work rotate synchronously and in the same direction, thus their points of contact are travelling in opposite directions thereby producing a relative movement between the surface of the work and the surface of the grinding wheel which is the combined movement of the two.

Rotation of the shaft 6 will effect one-to-one rotation of the grinding wheels G and the journals J but inasmuch as the wheels are very large a relatively slow rotation of the shaft 6, such, for example, as 400 R. P. M. will produce a relatively high peripheral speed such as is desirable for grinding. Rotation of the shaft 6 effects, not only rotation of the eccentrically mounted grinder Wheels G G G and G but it also causes those Wheels to revolve bodily about the axis of that shaft and as the angle and extent of eccentricity of each of those grinder wheels corresponds to the angle and extent of eccentricity of the crank-pin,

As shown most located at the right side of the machine. This hand wheel is fixed upon one end of a shaft 26 journaled in the carriage I and which carries pinions 21 and 28 meshing with racks 21 and 28 fixedly secured to theside frames 2 and 3, respectively. That end of the shaft 26 which carries the hand wheel passes through a slot 29 in the side frame 3. From the, foregoing it will'be apparent that rotation of the hand wheel '1 will cause the carriage 1 and all parts carried thereby to be adjusted lengthwise of the side frames 2 and 3. Any suitable means, such, for example, as adjustable stop screws 30 threaded through lugs 30 7 thrusts of the grinding wheels.

and 35? formed on the side frames, may be provided for limiting the movement of the carriage 'l and the Work carried thereby, toward the grinding wheels.

To prevent the workpiece from being deflected by the pressure of the grinding wheels thereon this invention provides an improved form of work-support which effectively resists all of the As hereinbefore stated this work-support is designated generally as S and comprises a slide 3! fitted to guideways 1, 'l formed on the carriage 1. These guidesways extend upwardly and 'rearwardly from the front end of the machine at an angle of 45. Carried by the slide 3!, is a plurality of steady-rests (one for each surface to be ground) each comprising a shank and a head having L-shaped work engaging surfaces. The steady-rests for the concentric journals J are mounted somewhat differently from the steady-rests for the revolving crankpins and the former will be described first, the numeral 32 being employed to designate their shanks and the numeral 33 to designate'their heads.

The slide 3] is formed with a plurality of upstanding ribs or walls 34, the upper portion of each of which is provided with a guideway 34 extending upwardly and rearwardly at an angle of 45 and which therefore is parallel with the guideways 1 and l on which the slide 1 is mounted. One of the shanks 32 of one of the steady-rests is fitted within each of the guideways 34 and an adjusting screw 35 threaded through a lug 36 and engaging the shank serves to adjust the steadyrest toward and frorrrthe workpiece. The head portion 33 of each of said steady-rests is provided with a Work-engaging element 31 of substantially L-shape, affording perpendicular workengaging surfaces 31 and 37 adapted to engage the journal J at two sides and thereby resist the outward and downward thrusts thereon produced by the grinding wheel.

The steady-rests for the revolving crank-pins are similar in construction to the steady-rests for the journals but they are so mounted and actuated that they each partake of a revolving movement corresponding to the revolving movement of the crank-pin it is adapted to support. In order more clearly to differentiate them from the journal steady-rests the shanks of' the crank-pin 43, which bars are supported at" their opposite ends on revolving crank-pins 44 which, with V crank-arms 45 and certain concentric portions 46, constitute crank-shafts designated generally as X and Y, jcurnaled at their opposite ends in the two outermost walls 34 of the slide 3|. It is to be understood that the angle and extent of eccentricity of the crank-pins 44 on which each of the bars 43 is mounted corresponds in angle and. extent of eccentricity to the crank-pin on. the workpiece'which the steady-rest, supported on said bar, is adapted to engage. Therefore, when the crank-shafts X and Y are'rotated synchronously with the workpiece each steady-rest will be given a revolving motion corresponding precisely to the revolving motion of the crank-pin it is adapted to support and therefore the surfaces 4 I and 4| will be maintained in supporting contact with the periphery of the crankpin. The steady-rests may be adjusted on the bars 43 by means of adjusting screws 41 threaded through lugs 43 projecting upwardly from the bars 43, and engaging the shanks 40.

The steady-rest actuating crank-shaft Y may be caused to rotate synchronously with the workholder 2|, and the workpiece W carried thereby, by means of a suitable drive shown most clearly in Figs. 1 and 3. This drive comprises a gear 48 secured to the spindle I8, which gear meshes with and drives an intermediate gear 49 journaled on a stud supported by the head-stock 8. The gear 49 in turn, drives a gear 50 secured upon a short shaft 5| also journaled in the headstock. Shaft 5| is connected, by means of a telescopic universal connection U with the crankshaft Y, thereby rotating the latter While permitting it to be moved bodily by movement of the slide 3|. The crank-shaft X is rotated synchronously with the crank-shaft Y and in the same direction by a gear train comprising a gear 52 secured to the crank-shaft Y, a gear 53 on the crank-shaft X and an intermediate connecting gear 54 journaled on a stud supported by one of the outer upstanding walls 34 of the slide 3|.

It is to be understood that the purpose of the steady-rest adjusting- screws 35 and 41 is to effect an initial accurate setting of the steadyrests to suit any type of crank-shaft to be ground and to compensate for any wear which may take place on the work-engaging elements 31 and 41. The steady-rests will be initially adjusted so that each of the work-engaging surfaces thereof will contact with the finished surface of a com pleted crank-shaft similar to the crank-shafts which the machine is thereafter intended to grind. After this setting has been effected all of the steady-rests are retracted from the workpiece by moving the slide 3! downwardly on its ways and a similar, but unfinished, crank-shaft is secured in the work-chuck 2| and supported on the dead center 22. This retraction of the steadyrests may be accomplished by means of a lever F secured upon a shaft 55 journaled in the carriage 1. A gear 56, secured upon the shaft 55 meshes with a rack 57 secured to the underside of the slide 3|. Therefore rotation of the shaft '55 by the lever F will effect retraction or ad-' 'vance of the slide 3| Any suitable defent means,

such, for example, a pin p carried by the lever F and adapted to be fitted into a suitable aperture in the carriage 1, may be provided for holding to supporting contact with the portions of the work they are adapted to support. One embodiment of such means is illustrated as comprising a weight Z secured upon one end of a cable 58, the other end of which is wound about a sheave wheel 59 secured upon the shaft 55. It is to be understood, however, that any other suitable mechanical, hydraulic or electrical means may be substituted for the embodiment disclosed.

Inasmuch as the machined but unfinished workpieces as placed in this machine are not truly accurate, it is probable that the journals and crank-pins thereof will be of various sizes. The grinding wheels, however, are all of accurate size and therefore it is likely that when the rotating workpiece is moved toward the rotating grinding wheels that one of the journals or crank-pins which is most oversize, will engage its complemental grinding wheel but the others will be held away from their grinding wheels until the diameter of the most oversize portion is somewhat reduced by the action of the grinding wheel, whereupon the next most oversize portion will engage its grinding wheel. Thus the successive engagement and grinding of the various portions continues until they have all been finished and reduced to the proper diameter. Inasmuch as the steady-rests had previously been set to a finished workpiece and are urged toward their respective work portions by the weight Z only that steadyrest which corresponds to the most oversize journal or crank-pin will engage the work at first. As the diameter of this portion is reduced the steady-rest corresponding to the next most oversize portion of the work will engage its work portion the same time that the grinding wheel starts to operate thereon. From this it will be apparent that no portion of the workpiece is ground without there being a steady-rest acting thereon to resist the thrusts of the grindingwheel and that therefore the resistance to defiection of the workpiece increases in proportion and in direct opposition to the increase in the stresses placed thereon by the grinding wheels. It is of course necessary that the grinding faces of the grinding wheels be maintained smooth and true. However, as those eccentrically mounted grinding wheels which are adapted to grind the crank-pins revolve bodily about the axis of their drive shaft, as well as rotate, conventional wheel dressing devices may not be employed. This invention provides an improved wheel dressing device by means of which all of the concentrically and eccentrically mounted grinding wheels may be dressed simultaneously. This device comprises the translatable table II, hereinbefore mentioned, which carries a plurality of upstanding walls 60 each carrying a suitable diamond point d adapted to dress one of the concentrically mounted grinding wheels G. Journaled in the two outside walls 60 are two similar crank-shafts H and I formed with a plurality of crank-arms 6 I, 6| respectively, supporting crank- pins 62, 62 Upon each adjacent pair of crank-pins l5l62 there is supported a link or plate 63 which carries at its forward end a suitable diamond point 11 adapted to operate on one of the eccentrically mounted grinding wheels. Each pair of complemental crank- pins 62, 52 upon which each diamond supporting link 63 is mounted, has an angle and extent of eccentricity with respect to the axis of its crank-shaft which corresponds to the angle and extent of eccentricity which the center of the grinding wheel (which the diamond supported by that plate dresses) bears to'the axis of the shaft 6. The crank-shafts H and I are rotated synchronously with the grinding wheels and therefore each wheel dressing diamond d has a revolving motion which corresponds to the revolving motion of its associated grinding wheel and therefore the diamond is maintained in dressing contact with the grinding wheel during revolution of the latter.

The crank-shaft H is rotated synchronously with the grinding wheels, by means of a gear connection with the shaft l1, comprising a pinion E54 splined to the shaft l1 and a gear 65 fixed to a sleeve 66 Journaled in a standard 61 carried by the table 10. The standard In also supports the pinion 64 and maintains it in mesh with the gear 65. One end of the crank-shaft H has a splined telescopic connection with the sleeve 65 whereby the crank-shaft is rotated thereby and is permitted to move endwise therein during translation of the table I l. The crankshaft I is rotated from the crank-shaft H through gears 68, 69, and 10.

The table I I, carrying all of the wheel dressing tools, may be reciprocated back and forth on its guideways ID, to cause the dressing tools to traverse the faces of the grinding wheels, by means of a manually rotatable screw H journaled in the table l and engaging a suitable nut 12 secured to the underside of the table II (Fig. A hand-wheel l3 affords convenient means to rotate the screw H.

In order to compensate for reduction in size of the grinding wheels because of wear and dressing the table I0 is adjustable toward the grinding wheels. This adjustment may be effected, similarly to the adjustment of the carriage l, by means of racks 14 secured to the side frames 2 and 3 and pinions 15 secured to a cross-shaft 16 carried by the table and engaging said racks. One end of the shaft 16 projects through a slot H in the side frame 3 and is provided with a hand wheel 18 by which the shaft may be rotated. Stop screws 19 supported by the side frames limit the inward movement of the table The foregoing describes one embodiment of this invention in which the workpiece and the grinding wheels are rotated synchronously. Figs. 9 and 10 illustrate diagrammatically another embodiment in which the work-holder 2| and the workpiece W, carried thereby, are rotated at one-third the rate of the eccentrically mounted grinding wheel G". This difference in rate of rotation is effected by the ratio of the gears l3, l4, l9, and 20' by which the workholder is rotated from the grinder wheel shaft 6. With this relative rate of rotation of the grinding wheel and work one revolution of the grinding wheel (from the position shown in Fig. 10) will cause its periphery to approach and recede from the axis of the workpiece while the latter is making a partial rotation of 120, thereby grinding that portion of the periphery thereof designated by the reference character a. During successive revolutions of the grinding wheel the portions b and 0 will be ground.

Likewise other shapes may be ground by further varying the rate of rotation of the workpiece relative to the rate of revolution of the eccentrically mounted grinding wheel and, if desired, by effecting a relative axial movement between the grinding wheel and the: work. Fig.-

H illustrates at W" a form "of workpiece which may be ground by rotating the workpiece twice to each revolution of the eccentrically mounted grinding wheel G 7 V V Withoutfurther analysis, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt it for various utilizations by retaining one or more of the features that, from the standpoint of the prior art, fairly constitute essential characteristics of either the generic orspecific aspects of this invention and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims.

Having thus revealed this invention, I claim as new and desire to secure the following combinations and elements, or equivalents thereof,

by Letters Patent of the United States:.-

1. A machine for grinding the surface of a cylindrical portion of a workpiece arranged eccentric to the axis of the workpiece combining means to rotate a workpiece on its axis thereby to cause said portion to revolve about said axis; a circular grinding wheel; means to cause said grinding wheel to engage said cylindrical surface; a steady rest ior supporting said portion during its revolutions and means to rotate said grinding wheel and to give to it a revolving motion similar to the revolving motion of said portion of the workpiece, thereby to maintain said portion and grinding wheel in grinding contac during rotation of the workpiece.

2. A grinding machine for simultaneously grinding cylindrical portions of a workpiece arranged concentric with the axis of the workpiece andother cylindrical portions arranged eccentrio to the axis thereof, combining means to turn a workpiece on its axis thereby to rotate said concentric portions and to cause said eccentric portions to revolve about said axis; a circular grinding wheel adapted to operate on each of said portions, means to effect relative movement between said workpiece and said grinding wheels to cause the latter to contact with said cylindri- Vcal portions; means. to rotate said grinding Wheels; continuously operative supports for said concentric and eccentric cylindrical portions and means to giveto those grinding wheels which operate on said eccentric portions movements 'corr'esponding to the movements of said eccentric portions thereby to maintain said grinding wheelsin c'ontact with the eccentric portions dur- 7 ing revolution thereof. 7 g

3. In a grinding machine adapted sinmltitneous- 1y to grind a first cylindrical portion of 'a workpiece arranged concentric with the axis thereof and a second cylindrical portion arranged eccentric to said axis means to rotate said workpieceonits axis; a rotatable shaft journaled parallel to the axis of said workpiece; a first circular grinding wheel secured tosaid shaft with'its axis concentric with the 'axisofsaid shaftand adapted tooperate on said first portion of the work-piece;

- to the eccentricity of=-saidsecond. portion to. the

asecond circular grinding'wheel secured to said shaft-with its axis eccentric to the axis of said shaft andadapted to operate on said second portion: of the workpiece; the eccentricity of said second grinding wheel tosaid shaft corresponding axis of the workpiece; means to bring said grinding wheels andsaid portions of the workpiece into grinding contact; means supporting each of said portionsduring the grinding operation and means to rotate said shaft synchronously with the rota- 7 tion of said workpiece. (.55

4, A machine for simultaneouslygrinding the Wheels with respect to said fixed center corre- V sponding to the angle and extent of eccentricity of its associated crank-pin to the axis of said crank-shaft; individual supports for said crank pins; means to synchronize the revolutions of said crank-pins and their respective grinding wheels; and feed means to effect relative adjustment between the crank-shaft and said grinding wheels. and between said crank shaft and said supports to maintain said journals and crankpins in grinding 'contact with their respective grinding wheels and said supports in engagement with said crank pins. 7

5. In a machine for simultaneously grinding all of the crank-pins of a crank-shaft, means to rotate a crank-shaft about its longitudinal axis thereby to cause said crank-pins to revolve about said axis; a plurality of grinding wheels each adapted to. operate on one of said crank-pins; means to maintain said grinding wheels in grinding contact with said surfaces during rotation of said crank-shaft; and a support for each of said crank-pins comprising a steady-rest adapted to engage the crank-pin to resist the thrusts of said grinding wheel; and means to maintain said steady rest in contact with said crank-pin during a complete rotation thereof.

6. In a machine for simultaneously grinding a plurality of eccentric portions of .a workpiece, means to rotate. a workpiece about its.- longitudinal axis thereby to cause said eccentric portions to revolve about said axis; a, plurality of; grinding wheels each adapted to operate on one tion of a workpiece arranged eccentric-to the axis: thereof, means to rotate said workpiece aboutits axis thereby tocause said portion torevolve about of said portions of. the workpiece; means to mainsaid axis; a grinding Wheel'adapted to operate on said portion; means to give to said grindingj wheel revolving motions corresponding: to the revolving, motionsof said portion of the workpiece; asteady;-.

rest for said portion adapted toresist thezthr-usts,

of said grinding wheel thereon; means to move said steady-rest into engagement with said work portion; and means to give to said steady-rest revolving motions corresponding to the revolving motions of said work portion thereby to maintain the'steady-rest i l-supporting contact there,- with throughout-a complete grinding operation.

8. In a grinding machinefor grinding a cylindrical portion of a workpiece arranged eccentric to the axis thereof, means to rotate said workpiece about its axis thereby to cause said portion to revolve about said axis; a grinding wheel adapted to operate on said portion; means to give said grinding wheel revolving motions corresponding to the revolving motions of said portion of the workpiece; a support for said portion of the workpiece adapted to resist the thrust of the grinding wheel thereon, said support comprising a carrier member; means including a pair of rotating crank-pins for supporting said memher and giving to it revolving movements corresponding to the revolving movements of said portion of the workpiece; a steady-rest adjustably mounted on said carrier member and having angularly arranged surfaces for engaging said workportion; means for adjusting said steady-rest on its carrier; and means operative during a grinding operation to shift said carrier member thereby to urge said steady-rest into supporting contact with said work portion.

9. A machine for supporting and grinding the cylindrical surface of a crank-pin of a crankshaft combining means to rotate a crank-shaft about its longitudinal axis, thereby to cause said crank-pin to revolve about said axis, a circular grinding wheel adapted to operate on said crankpin; means to bring said grinding wheel and crank-pin into grinding contact; means to give to said grinding wheels revolving motions corresponding to the revolving motions of said crankpin thereby to maintain said grinding wheels in grinding engagement with said crank-pin during rotation of said crank-shaft; a support for said crank-pin comprising a steady-rest adapted to engage said crank-pin at the side opposite the grinding wheel; and means to give to said steadyrest revolving motions corresponding to the revolving motion of said crank-pin thereby to maintain the steady-rest in supporting contact with said crank-pin during the entire revolution of the latter.

10. In a machine for grinding the surface of a cylindrical portion of a workpiece arranged eccentric to the axis of the workpiece, means to rotate a workpiece on its axis thereby to cause said portion to revolve about said axis; a circular grinding wheel; means to cause said grinding wheel to engage said cylindrical surface; means to rotate said grinding wheel and to give to it a revolving motion similar to the revolving motion of said portion of the workpiece thereby to maintain said portion and grinding wheel in grinding contact during rotation of the workpiece; a dressing tool for said grinding wheel mounted adjacent to the periphery thereof; means to adjust said dressing tool into contact with said wheel; and means to give to said dressing tool revolving motions corresponding to the revolving motion of said grinding wheel thereby to maintain them in operative contact during revolution of the grinding wheel.

11. In a machine for grinding the surface of a portion of a workpiece arranged eccentric to the axis of the workpiece, means to rotate a workpiece on its axis thereby to cause said portion to revolve about said axis; a circular grinding wheel; means to cause said grinding wheel to engage said cylindrical surface; means to rotate said grinding wheel and to give to it a revolving motion similar to the revolving motion of said portion of the workpiece thereby to maintain said portion and grinding Wheel in grinding contact during rotation of the workpiece; a support for said eccentric portion comprising a steady-rest adapted to engage said portion at the side opposite the grinding wheel; means to give to said steady-rest revolving motions corresponding to the revolving motions of the eccentric portion of the workpiece thereby to maintain the steady-rest in supporting contact with said eccentric portion during the revolution of the latter; a dressing tool for said grinding, wheel mounted adjacent to the periphery thereof; means to adjust said dressing tool into contact with said wheel; and means to give to said dressing tool revolving motions corresponding to the revolving motion of said grinding wheel thereby to maintain them in operative contact during revolution of the grinding wheel.

12. A grinding machine for grinding circular peripheries of eccentrically mounted workpieces combining a work support for rotating a workpiece on an axis non-coincident with the geometriccenter of the piece to be ground; a circular grind-wheel mounted to rotate upon an axis non-coincident with its geometric center; a wheel truing device operative upon said wheel in a direction radial to the geometric center of said wheel; means for giving said device a movement in space corresponding to the orbital movement of the geometric center of said wheel thereby to maintain said device effective radially upon said wheel in all positions of the geometric center thereof about its non-coincident axis of rotation; and means maintaining the ratios of the angular velocities of said workpiece, grind-wheel and truing device at predetermined constant values throughout a grinding operation.

13. A grinding machine for grinding the surface of a workpiece eccentric to its axis of rotation combining a work support for rotating a workpiece; a rotatable grind-wheel mounted eccentric to its axis of rotation for operating upon said workpiece; a Wheel truing device operative upon said wheel in a plane radial to the geometric center thereof; means for moving said device in a path corresponding to the path of movement of the geometric center of said wheel about its axis of rotation; means for engaging said wheel with said workpiece with the line of contact of wheel and workpiece occurring in a plane radial to and intersecting the geometric center of said wheel; and means maintaining the position of said truing device in said radial plane of the wheel, and the line of contact of said wheel with said workpiece in said radial plane throughout a revolution of said wheel.

14. A grinding machine combining a rotatable work holder; a grinding element adapted to operate upon the surface of a workpiece mounted in said holder; means to rotate said holder to present new portions of the surface of the workpiece held therein to the action of said grinding element; means for moving said grinding element in an orbital path while maintaining engagement thereof with the workpiece; a dressing device for truing the surface of said grinding element; means for moving said device in an orbit corresponding to the orbit of movement of said grinding element and means maintaining the movement of said dressing device and the movement of said grinding element in angular synchronism whereby said device continuously effects a truing operation upon said grinding element Without changing its position relative thereto; and means for rotating said work holder and the workpiece supported therein synchronously with the orbital movement of said grinding element.

eccentric combining means to rotate an eccentric upon an axis outside of its geometric axis; a rotatable circular grind-wheel; means mounting said wheel for rotation on an axis eccentric to its geometric axis in an amount equal to the ec-V centricity of the eccentric to be ground; a grindwheel truing device; means mounting said device for movement toward and away from said grindwheel in a plane radial to the geometric axis of said wheel; means formoving said device in a circle whose radius equals the eccentricity of the mounting of said grinding wheel; and means for maintaining the angular velocity of said truing device and the angular velocity of said grindwheel in angular synchronism thereby to maintain said truing device eflfective'in said radial plane throughout a complete revolution of the wheel. 7

16. A machine for grinding the periphery of a non-circular workpiece combining means to rotate a workpiece upon an axis; a circular grinding element; means mounting said element for rotation on an axis eccentric to its geometric axis in an amount equal to the eccentricity of the surface of the non-circular" workpiece to 'be ground; a wheel trulng device for said circular grinding element operative on the periphery of said grinding element in a direction radial to the geometric axis of said grinding element; means for moving said device in a path corresponding to the path of movement of the geometric center of said circular grinding element; and means for maintaining a one-to-one ratio between the angular velocity of said truing device and the angular velocity of said grinding element and a predetermined constant ratio between the angular velocity of said circular grinding element land the angular velocity of the workpiece throughout a complete revolution of said workpiece. a r i ADOLPH L. DE LEEUW.

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